竖直槽道内有限尺寸颗粒和湍流相互作用机理的数值研究

Particle-laden turbulent flows are ubiquitous in natural and industrial settings. Understanding of their mechanisms and accurate modeling of such flows are of great importance to the improvement in the efficiency of the relevant industrial devices. In this project, an interface resolved direct numerical simulation method is employed to investigate systematically the interactions between the spherical particles and turbulent vertical channel flows at relatively high particle volume fraction and different particle settling speeds, and the effects of particle non-spherical shapes and fluid viscoplasticity on the particle-turbulence interactions. We focus on the effects of the particle velocity fluctuation on the inter-phase average drag in a real particle-laden turbulent flow, and the effects of the ellipsoidal particles settling in a vertical channel flow on the flow drag. Our results can not only provide great insights on the interactions between the finite-size particles and turbulence, but also are helpful for improving the engineering multiphase flow models.

颗粒悬浮湍流在自然界和各种工业应用中普遍存在，了解颗粒悬浮湍流的动力学机理以及建立准确的预测模型对于提高相关工业设备的运行效率具有极大的意义。本项目拟采用双重直接数值模拟方法系统地研究竖直槽道内较高颗粒体积分数、不同颗粒沉降强度下球形颗粒与湍流的相互作用规律，以及颗粒的非球形形状和流体的粘塑性特性对颗粒-湍流相互作用的影响。本项目特别关注在真实的颗粒悬浮湍流中颗粒脉动速度对相间平均阻力的影响，以及竖直槽道内具有沉降效应的椭球颗粒对流动阻力的影响。预期研究成果不仅可以大力增进对有限尺寸颗粒和湍流的相互作用规律的认识，也可以为工程多相流模型的改进提供参考。

本项目采用双重直接数值模拟方法系统地研究竖直槽道内在不同颗粒体积分数、颗粒沉降强度、颗粒尺寸、颗粒-流体密度比和槽道雷诺数下球形颗粒与湍流的相互作用规律，以及颗粒的非球形形状和流体的粘塑性特性对颗粒-湍流相互作用的影响。研究成果大力增进了对有限尺寸颗粒和湍流的相互作用规律的认识，也得到了新的相间阻力模型以及雷诺应力模型。在本项目资助下，已发表SCI论文13篇（其中3篇JFM，3篇POF）。